Okay, On XP, this is what works for me:
In My Computer right click the drive, go to the share tab, select "Share this folder" and click the "New Share" button down the bottom. Enter this info:
Share Name: C$ (or drive letter)
Maximum Allowed: Selected
Click Permissions and under "Everyone" make sure they have at least "Read" Allowed.
Click OK to close everything and then try: "\\ComputerName\C$" on the networked computer.
Works for me and I get all subfolders. Also set the Permissions to allowed Full Control and Writing if that's what you want, but "Read" MUST be allowed.
"Computers are useless they can only give you answers."